Diclofenac is a non-steroidal drug which was invented at the end of the sixties by A. Sallmann and R. Pfister (NL-6,604,752 and U.S. Pat. No. 3,558,690 both to Ciba-Geigy) and whose structural formula is indicated below.

Diclofenac is widely dispensed and used owing to its well-known analgesic, anti-pyretic, anti-arthritic, anti-phlogistic and anti-rheumatic properties. It is generally taken orally in the form of normal tablets or tablets covered with coatings resistant to gastric juices, or rectally, or by injection, or topically.
The possibility of taking it in the form of sweets, tablets dissolving in the mouth, drages, chewing gum or other similar pharmaceutical forms or in formulations for the extemporary preparation of diclofenac-based aqueous solutions and/or suspensions would represent a different mode of administration which is definitely more suitable, especially for children and elderly persons.
Owing to its poor solubility in water, diclofenac is normally used in salt form; the salts of diclofenac customarily used are those of sodium, potassium or other alkali and alkaline earth metals, together with salts of organic nature, such as the salts of basic amino acids, such as lysine, arginine and ornithine, or other pharmacologically acceptable organic bases which have the ability to render the resulting salt soluble in water.
The pharmaceutical compositions of the diclofenac salts for oral use are generally 25 accompanied by side effects of not inconsiderable consequence: Diclofenac salts are in fact characterised by a particularly unpleasant and bitter taste and by the fact that they produce a sensation of strong astringency and cause an especially intense form of irritation in the buccal cavity, especially in the area of the larynx.
Although the first problem has been partly solved by using flavourings which are able in some manner to mask the taste, satisfactory solutions have still not been proposed for the two remaining problems.
Therefore, the pharmaceutical compositions containing diclofenac salts still have a poor palatability which limits their adoption and possible fields of application, despite the excellent therapeutic effect with which they are associated.
A second problem connected to diclofenac is that, when it is orally administered by means of immediate release formulations, the corresponding Tmax (the time to the maximum plasma concentration) is usually located at about 1 hour since administration, this being of course a not completely satisfactory result when a prompt and strong analgesic/anti-pyretic effect is sought for. Furthermore, the corresponding coefficient of variation is normally in the range of 70-90%, which means that the Tmax is strongly variable and dependent on the physical characteristics of the patient (Physicians' Desk Reference, 52 edition, 1998, pag. 1831). Attempts are therefore still being made in order to enhance the rate of absorption of diclofenac and to provide an earlier onset of the therapeutic effect (N. Davies, K. Anderson; Clinical PharmacokineticS of Diclofenac, Clin. Pharmacokinet., 1997, September 33(3)).
The object of the present invention is therefore that of providing a fully palatable formulation of diclofenac which is able to generate a more rapid, uniform and foreseeable release of the active principle if compared to the compositions known in the art and presently available on the market. For the purposes of the present invention Tmax means the time to the maximum plasma concentration whereas Cmax is the maximum plasma concentration of the active principle, namely diclofenac.